Hi love your videos best education for me since I am just starting to learn how to repair boards. I am working on a centipede board and I have repaired it and it is up and going on the bench but the trackball just goes to the left and doesn’t move. I tested the movements and they are changing states at the chips and I see .7v to 4.9v from the trackball but still no change and it doesn’t work. Any advice I tested the 74ls191 74ls74 74ls157 40106 and they all perform fine
You are in the correct location. I can offer anything additional off the top of my head. Your best bet is to start a repair thread on KLOV. Good luck and report back if you figure it out.
JACKLICK, Arcade Address Error Question All the data signals and address signals look good on the oscilloscope even when the addressing has errors. How would an arcade repair technician know there is an "addressing error" when all the data signals and the address signals look good on the oscilloscope and all the ROM and RAM test good on the ROM/RAM tester?
You know I am not an expert right? :) I appreciate the questions anyway and hope I don't ever answer too confidently. Always take my responses with some skepticism. Measuring these data or address lines with a scope just shows whether they have activity or not. As you state, it doesn't mean the data on the line is correct. You will need a fluke 9010 microprocessor troubleshooter or a signature analyzer (with NOP adapter) to see if the data you send/expect is actually correct. One of my upcoming videos will be on signature analysis. It is easier with the fluke but yea it is hard to track this crap down. Hopefully there are clues you can see on screen that lead you to an area on the schematic to narrow things down.
@@jacklick thanks for the help I thought a Signature analyzer would only verify if the ROM chips are good or bad. The Signature analyzer can't test if the RAM chips are good or bad or is the addressing is correct or has errors?
I haven't used my sig analyzer to this extent, yet, but when combined with a No Operation Instruction (usually via a NOP cpu adapter) the cpu becomes a 16bit synchronous counter. You can grab signatures pretty much anywhere on the address bus. The downside is you need known good signatures to compare to. These are often included in Atari schematics for example.
@@jacklick can you show how to use the sig analyzer with a NOP no operation instruction to test the ROM and RAM chips on an arcade game board in a future youtube video because I don't understand how this would work to test the ROM and RAM chips.
Will do. I am making an assumption it is possible because I know there are SA "signatures" for Rom output lines in the schematics. My theory/assumption is the a specific address/memory area is being triggered by the NOP via address lines which causes the rom to put that data on the data line. Again, I haven't actually done it yet and it is still murky to me but look forward to hopefully figuring it out or failing while trying :)
Hi I really love your videos and it inspired me to start learning how to repair boards. I repaired 7 defender sets and 4 stargate sets. I just got a centipede board and I repaired it to the point where I get an almost working game with half the screen with jumbling characters. I don’t have the game harness with the test switch and I was wondering if you could help me how to get it into test mode any help would be greatly appreciated Phil
Nice to hear and congrats on repairs. I would look at the schematic and trace back where test comes into the pcb card edge. You can just gnd finger 13 of the card edge as well. good luck.
@@jacklick thanks so much for the info I tried looking at the schematic and I can’t find the test switch in them. I only see schematics for playfield video audio coin door and etc but I can’t seem to find the test. You say finger 13 so that’s opposite of M right? Do I have to keep it grounded or just momentarily? Thanks again and thank you for all your videos it has inspired me to pursue board repair which I’m finding so interesting
Also I connected the video output on my board directly to the points on a video composite cable but it didn’t show anything, is it because I am using a normal CRT tv with a standard composite cable? Should I do something else to get video?
Thanks for what you are doing
My pleasure! Thanks for the comment.
Hi love your videos best education for me since I am just starting to learn how to repair boards. I am working on a centipede board and I have repaired it and it is up and going on the bench but the trackball just goes to the left and doesn’t move. I tested the movements and they are changing states at the chips and I see .7v to 4.9v from the trackball but still no change and it doesn’t work. Any advice I tested the 74ls191 74ls74 74ls157 40106 and they all perform fine
You are in the correct location. I can offer anything additional off the top of my head. Your best bet is to start a repair thread on KLOV. Good luck and report back if you figure it out.
JACKLICK,
Arcade Address Error Question
All the data signals and address signals look good on the oscilloscope even when the addressing has errors. How would an arcade repair technician know there is an "addressing error" when all the data signals and the address signals look good on the oscilloscope and all the ROM and RAM test good on the ROM/RAM tester?
You know I am not an expert right? :) I appreciate the questions anyway and hope I don't ever answer too confidently. Always take my responses with some skepticism. Measuring these data or address lines with a scope just shows whether they have activity or not. As you state, it doesn't mean the data on the line is correct. You will need a fluke 9010 microprocessor troubleshooter or a signature analyzer (with NOP adapter) to see if the data you send/expect is actually correct. One of my upcoming videos will be on signature analysis. It is easier with the fluke but yea it is hard to track this crap down. Hopefully there are clues you can see on screen that lead you to an area on the schematic to narrow things down.
@@jacklick thanks for the help
I thought a Signature analyzer would only verify if the ROM chips are good or bad. The Signature analyzer can't test if the RAM chips are good or bad or is the addressing is correct or has errors?
I haven't used my sig analyzer to this extent, yet, but when combined with a No Operation Instruction (usually via a NOP cpu adapter) the cpu becomes a 16bit synchronous counter. You can grab signatures pretty much anywhere on the address bus. The downside is you need known good signatures to compare to. These are often included in Atari schematics for example.
@@jacklick can you show how to use the sig analyzer with a NOP no operation instruction to test the ROM and RAM chips on an arcade game board in a future youtube video because I don't understand how this would work to test the ROM and RAM chips.
Will do. I am making an assumption it is possible because I know there are SA "signatures" for Rom output lines in the schematics. My theory/assumption is the a specific address/memory area is being triggered by the NOP via address lines which causes the rom to put that data on the data line. Again, I haven't actually done it yet and it is still murky to me but look forward to hopefully figuring it out or failing while trying :)
Hi I really love your videos and it inspired me to start learning how to repair boards. I repaired 7 defender sets and 4 stargate sets. I just got a centipede board and I repaired it to the point where I get an almost working game with half the screen with jumbling characters. I don’t have the game harness with the test switch and I was wondering if you could help me how to get it into test mode any help would be greatly appreciated
Phil
Nice to hear and congrats on repairs. I would look at the schematic and trace back where test comes into the pcb card edge. You can just gnd finger 13 of the card edge as well. good luck.
@@jacklick thanks so much for the info I tried looking at the schematic and I can’t find the test switch in them. I only see schematics for playfield video audio coin door and etc but I can’t seem to find the test. You say finger 13 so that’s opposite of M right? Do I have to keep it grounded or just momentarily? Thanks again and thank you for all your videos it has inspired me to pursue board repair which I’m finding so interesting
I found the self test right where you said I can’t believe I missed it thanks again
Mine was doing the thing at the end and it looked like it was raining sideways, how did you fix that?
Also I connected the video output on my board directly to the points on a video composite cable but it didn’t show anything, is it because I am using a normal CRT tv with a standard composite cable? Should I do something else to get video?
I just adjusted the Horizontal or Vertical Hold.
that should work. just hook up gnd and the video out to composite connection.